Vertical self-priming pump



Aug. 7, 1945.

VERTICAL SELF-PRIMING PUMP Filed March 8, 1944 H. LA BoR 2,381,824

4 Sheets-Sheet l INVENTOR.

ff M5 f w @Off B mafauw 4 Sheets-Sheet 2 Filed March 8, 1944 Allg. 7, 1945. H.. E. LA BQUR uw 2,381,824

yVERTICAL SELF-PRIMING PUMP l iled March 8, 1.944 4 sheets-sheet s r l l |l l 2g I" my Y lil 28@ v I K v I" l i hll IN VEN TOR.

Aug 7:1945' f H. E. LA BoUR 2,381,824

. VERTICAL SELF-PRIMING PUMP UNITED STATES PATENT l l a 2,381,824

orifice 2,331,824 vsn'ncm. sum-ramo PUMP' nan-y E. L. Buur, mum, Ind. Appunti@ nach s, 1944, serial N0. 525,529

(ci. 1oz-113) 25' Claims.

present invention is described of speeds. For example, a 4disk of about 41/4" while designed for 3450 R. P. M. is operative with is a vertical pump suitable for acid service, but y the immenenti; herein disclosed are intended to be employed in other types of self-priming pumps and miner iields of use where applicable.

Centrifugal pumps of the self-priming type have certain inherent problems, the chief one of which is the sealing of the shaft. A self-priming pump imposes its suction upon the shaft seal and any leakage at that point reduces the eiiicency and the eective lift of the pump. In the pump of ihepresentinvenon a. novel form of liquid y seal and impelier embodying the principle of my appiioaon, Ser. No. 439,308, filed mii-1?, 1942, is utilized. Previous embodiments n! that primpie have involved certain compiexinfes am diilimilhes of construction and servicing wmch it is one of the objects oi the present invaitinn to simplify andobviate. One specic iltrisLumiereeneirtigrn;seti creertain ininted paris subject on one side to suction, but requim to be separable for servicing and renewai of parts. The present seal, shaft, and impalier consn'uction is designed to be suitable for' embodnnent in pumps of various material, such as of cest metal or of porcelain, or o other suitable materials. In the various embodiments herein disclosed, the structure has been organized to simplify the problem of construction, and more f portnntly, the problem of servicing, and rema! of the impeiler, without danger of introducing leaks which would seriously impair the' emciency of the pump. The preferred organizatlonoffheimpelierandseal housing issuch as 'to permit of ready removal of the shaft, the imnella'. and the seul as a imit. Replmement may thm he made in the iield by unskilled attendants.

. is of importance.v Theseal herein diaclnscd is capable of operatingwithout losing its liquidrand without discharging liquid during my phlse of operation. The seal may be consli-noted in various diameters, each to be operasuction over afairly wide range water and under high vacuum down to 2900 R. P. M., and at lowered vacuums at speeds as low as 1750 R.. P. M. 'I'he effectiveness of the seal increases directly as the specic gravity.' Reference herein to the conditions under which the seal operates is tov be understood to relate to the employment of water as the sealing liquidi Obviously, the specific gravity of the liquid must rbe taken into account in determining the speeds and dimensions required to withstand a. given pressure diierence.

The seal using a 7" disk may be used to hold maximum suction at 1750 R. P. M. While the impeller diameter and the seal channel diameter are illustrated as being the same,l the impeller diameterV may be greater than the seal channel diameter if so desired.

' of self-priming pumps operating under thefhy- 4into contact with the impeller.

A second major probleml of pumps of this class has todo with priming. Pumps of this class are usually subjected to tests to determine at some predetermined speed or range of speeds for which the pump is designed, the characteristics of rate o! priming, that is, the rate of air removal, the maximum dry suction attainable, and the emciency of pumping liquid for which the pump is designed. The requirements for Arapid priming, the requirements for maximum .dry suction and the requirements for high pumping eiiicency are divergent. Features favorable to high pumping eiiiciency are generally unfavorable, or even contradictory, .to good air handling ability, end/or high, dry suction. y

From numerous tests of the air handling ability draulic balance principle of my aforesaid patent, I have observed that'when the test extends to maximum dry suction the priming operation tends to proceed through three successive stages.'

The irst stage.' assuming the pumpy starts with atmospheric pressure on'both its suction side and on its discharge side, involves the initial withdrawal of air. As soon as the impeller starts to rotate, it throws substantially all of the priming liquid which is trapped in the suction connection and the impeller casing out into the discharge chamber or separator. Thereupon liquid tends to iiow back through the main and priming throats However, the tendency of the impeller to block reentry, both by the blocking effect of the blades and by the'impact effect oi liquid beck through the aforesaid port slows down the reentry of priming liquid. The i'orcetending` to feed-liquid from is only the small static head of liquid in the separator. The lack ofability-of the liquid to return in sufiicient amount to make up an adequate amount of air carrying mixture to viill the discharge throat results in ,a phase of operation known as a "priming stall." The air removal during this stage is slow'. However, as soon as enough air has been removed to produce a sub` stantial pressure difference, that pressure difference, added to the static head, begins to, return enough liquid to produce a ow of mixture which '2,381,824 a the separator back through the priming throats of one of the discharge passageways'. This, for example, may be a hole or slot in the upper wall of the main passageway at a point near its junction with the impellerJ chamber. The rst method of overcoming the priming stall involves introducing liquid into the impeller through an auxiliary port preferably by way of the clearance of a rotating part witl a stationary part of the casing. vThis opening may serve 'as a continuously open port with the pressure continuously in one direction, though preferably the pressure fills the discharge throat, that is, the main throat.

is reduced as the pump is primed Preferably the auxiliary opening comprises an open port in which the pressure reverses upon the pump lling its suction with liquid and attaining its discharge pressur. Thus, by utilizing the hydraulic balance principle upon the aforesad auxiliary port the inemciency which would result from a constantly open bypass between discharge and sucliquid vehicle decreases, so that at maximum vacuum there is no air removed. The pump is not able to retain a mixture of air and liquid up to the point of discharge and to discharge the mixture out of the impeller. .Y

. During theV aforesaid priming stall it appears from my investigation of the difiiculty that so small an amount of liquid reentersythat the density of the medium, li. e., mixture of air and Water is so low that no effective discharge pressure isdeveloped in the main throat. In the case of a horizontal shaft pump the air in the impeller casing tends to gravitate up through the main throat and through the liquid in the y separator. and gradually an orderly circulation is established. In the presentform of vertical shaft pump the establishment of an orderly ycirculation, i. e., reentry of liquid at the priming throat, formation of a mixtureand discharge', at the main` throat is much more diiiicult. It

appears that upon initial emptying ofthe impeller, chamber and iilling -of the same with air,

and mixing ofthe air with a small amount of remaining and reentering liquid creates a slightinternal pressure. 'Ihis internal pressure may not be great enough to overcome even the' small head of liquid in theseparator. Air appears to be driven into the throats, but withv lnsu'ilicient force to establish a substantialdischarge. This air pressure appears at times to establish an air lock in the priming throat which discharges downwardly, and this air lock prevents inflow of liquid. At the main throat the pressure is' so low as to fail to establish an eil'ective discharge,

might enter at this point. The result is that the initial pickup of suction is veryslow as compared to the rapid air evacuation that occurs as soon as an orderly circulation is established.l

I have discovered that it is possible to break the priming stall," time required to establish an orderlypriming now by either one of two methods'. One method involves introducing liquid through an auxiliary opening which may be at any suitable place which wm let liquid from the separator new into the impeller ata point not subject to air lock,

as, vfor example, through the clearance around the sealing box or channel member. The other method involves the provision of an opening which allows air to gravitai'e out of the throat trape so that the 46 the present design of pump and the impeller tends to drive back liquid that i. e;, greatly shorten the" into the separator,

.'ceeding priming quired for overcoming the priming stall.

A further problem of pumps of this type has to do with what happens when the pump yimpeller slows down to a stop. and the discharge and rsuction columns drop back due to gravity. One diiiiculty with self-priming pumps in general is the tendency for the liquid to drop back so rapidly as to pull the priming charge of liquid out-of the pump, particularly by therush of air thatfollows the retreating column of liquid down the suction pipe. I-Ieretofore, solution has been attempted-by increasing the size of the intake air following the column down should bubble up through the liquid in the intake trap, and leave suilicient liquid for the sucoperation. While that was possible. with a single pair of throats, and in pumps of relatively small capacity. it is found that in wherein multiple pairs of throats are employed, and particularly where the pump is of the vertical type, the liquid tends togo out of the separator, the pump and the intake trap so rapidly, and withv such a rush of air as to require too large an intake trap to be practical. I am aware .that it has been proposed to employ avalve in the suction pipe, or suction connection of the pump, which will check the return flow, or, as disclosed in my copending application, Serial No. 439,308, filed April A1'1, 1942, to insert a f low retarder in the suction connection. But I h'ave discovered that 'in a pump of the type employing a liquid seal .retardation of the now of liquid back into the pump from the discharge pipe produces the dewhile allowing the column in the suction pipe to drop asrapidly as it will,

the vacuum in the intake being broken by' air drawn down through the liquid seal.A While this from the separatorlls would appear toempty the seal of liquid, nevertheless the organization of the pump is such that liquid flowing into the impellerchamber the seal even though the intake trap should be completely emptied of liquid by the outrush of air entering through the sleeve and the sealing gap.

With this arrangement it is possible to reduce the intake trap to a relatively small chamber of only sufficient size to give good distribution around the impeller. The pump is thereby rendered' more compact, or for a given volume, greater space is permitted in the separator where the necessary work of air elimination from the priming liquid is carried on.

So far as I'am aware no one has seen how to build a self-priming porcelain pump, much less how to make the parts which must necessarily be vmade of metal adaptable to interchangeable use for a porcelain pump as well as a metal pump. The pump of the present invention accomplishes this. A difficulty with porcelain is the inability to endure a concentrated `stress particularly in tension. I conceived the possibility of employing porcelain in such a manner as to avoid concentrated stresses and to make the pump producible in porcelain. The pump is divided into parts which are producible in porcelain and the parts are shaped to. withstand the uid pressures andthe mechanical stresses to which the parts are subjected. The parts which must be made of metal involve a minimum in contact with the liquid to be pumped. This results in a, great saving in critical materials, at present'a very desirable' object. A

Another difliculty which I have encountered in pumps of this character, particularly vertical self-priming pumps, is the problem of preserving the bearings against contact with the liquid be ing pumped. `The preferred embodiment of the pump herein illustrated is Adesigned for handling corrosive liquids, and it is highly important' to keep the liquid and vapor therefrom 'out of the bearing spacey otherwise corrosion of the bearings, particularly of the anti-friction type, re-

. sults in rapid wear and destruction of the same.

I have provideda simplified and novel form of shaft bearing seal against the entry of liquid which might creep or be projected up along the shaft. This comprises a circular channel sealed with lubricating oil, preferably that which has passed through the bearings and vwashed them out, and a stationary ring which contacts with the oil in the channel to maintain a seal.

Certain mysterious failure of the bearings originally encountered, was nally diagnosed as due to breathing 'induced by changes in temperature in the parts defining the hollow space between the shaft and the bearing barrel causing corrosive vapors given off by the liquid pumped to' be drawn into the said space and` condensed in contact with the anti-,friction bearings with consequent corrosion of the same. Numerous expedients Awere tried to overcome this, but the final solution herein embodied is a removable ller block, which while permitting the withdrawal of the bearings, serves the purpose of Areducing the space to so minor a clearance that the breathing effect is substantially eliminated, and no vapors are drawn into thebearings.

The present pump is organized to permit the employment of porcelain Afor the parts which constitute the structural Awalls of the chambers. Those parts which require high strength and resistancel -to shock. must necessarily be made of metal. Such parts are the impeller and its shaft and driving parts, the sealing sleeve and disk and channel member.

Other and concomitant improvements will be -apparent from the following `detailed description and the claims.

`Now incrder to acquaint those skilled in the art with the manner of constructing and operating the device embodying my invention, I shall describe, in connection with the accompanying drawings, a specific embodiment of the same;

Figure l is 'a vertical, longitudinal section through the preferred embodiment ofthe present invention; l

Figure 2 is a plan view of a, detail, namely, a locking washer;

Figure 3 is a fragmentary, sectional view, showing a modiiied form of auxiliary priming port;

Figure 4 is a top plan view of the impeller and sealing box housing, with unitary ducts and associated flanges;

Figure 5 is an lelevation of the same on the une 5 5 of Figure 4;

Figure 6 is a vertical, longitudinal section of the impeller and sealing box housing, taken on the line 6-6 of Figure 4;

Figure 'l is a diagrammatic developedsection through the center line of main throat and duct taken on the line 1-1 of Figure 4; p

Figure 8 is a similar diagrammatic developed section lthrough the center line of the priming being generally transverse to cylindrical walls 2( The cylindrical Walls 2 have an extension 5 above the upper transverse wall 4, which extension wall 5 is provided with an annular flange 6 upon which rests a supporting ring 1 for mounting the bearing barrel 3, and the motor support 9. The motor support is adapted to receive a vertical electric motor, not shown, direct coupled to the driving l shaft 60.

The body of the pump is divided into an upper lsection I0, and a lower section I2, joined to- 1 gether in the particular embodiment shown in Figure 1 by the clamping ilanges I3 and Il," which are piloted together for ready assembly as indicated at I5. A thin gasket between angel I3, I4 may 'be provided.

A centrally disposed and concentric annular wall I6 integral with the upper closure wall l, or the adjacent side walls 2 if preferred, defines an intake-trap or intake chamber Il which communicates through an opening in the saidpupper wall 4 with an intake or suction connection I8- which is shown in dotted lines in Figure 1 for y the sake of clarity of illustration. In the actual pump the neck or suction connection I8 is disposed generally diametrically oppositeI the 'discharge neck or connection I9, but obviously the angular position of the two necks with respect to each other is optional.

The space inside the hollow body and outside of the'intake chamber i1 forms a separator chamber 20. This separator chamber 20 functions when the pump is not in operation to trap entrain gas fromllquid as is well understood by those skilled in the art. f

The intake chamber wall I8 has an inwardly extending flange 22, the lowermost surface of 1 which, indicated at 23, is nished oil to form the top side plate of the impeller chamber.

'I'he impeller chamber is defined by a cup-shaped member 24, which has cylindrical walls, the upper ports for the main discharge ducts 28a, 28a, and

the openings or ports 29 constitute the priming liquid, and. in the operation of priming to dis' is a. semi-enclosed impeller. The disk 93 has a 'depending flange 34 which is threaded interiorly to receive the threaded flange t5 on the disk 36, which latter disk forms the bottom of the sealing box or sealing channel member. An outwardly extending ilange 31 provides a v Ashoulder againstwhich the end of the dependports which open into the priming ducts 29a, 29a.- l

The ducts 2da extend outwardly substantially in the plane of the openings 28, and discharge their contents above the iiange segments 30, 30, whereas, the priming ducts 29a, '29ar are led downwardly, and open out below the flange segment 30, as will be apparent from Figures 4 and 8. 'I'he throats 28 and 29 are narrow slotlike throats embodying the invention of my prior Patent No. 2,291,478, and ofmy copending application, Serial No. 439,308, filed April 17, 1942, these openings 28 and 29 being of less width than the width of the blades 21. The oblong outline. 2lb :in Figure 7 is a development of the actual throat opening 28. Likewise in Figure 8 the oblong outline 29h is a development of the actual throatopening 29. It is to be observedthat the throat openings l28 and 29 are of approximately the same width. lI'hey are located in ing threaded flange 34 abuts, and these two parts, 3| and.31, may be welded together to provide a unitary structure which is leakproof. The bottom wall 36 of the sealing box is in this embodiment formed integral with the impeller shaft 38. This construction provides an integral leakproof seal box or sealing channel member.

A sealing sleeve 39 has a shoulder di hearing against the edges of the annular flange El formed on the bottom of the wall l against which it is clamped by a nut 94 threaded upon the reduced upper end of said sleeve. The sleeve below the upper threaded portieri is provided with a shoulder so as to receive a yielding packing ring 93 under the locking washer 95. The locking washer 85 shown in plan in Figure 2 has a keying projection 96 entering a keyway formed in the part of the impeller chamber which has greater clearance. This feature of greater clearance for the seal box is optional. 'I'he main' "throat 23 is of approximately twice the length of the bypass throat. 'I'he significance and novel 1 mode of operation introduced by this ratio of .the throats is fully explained and disclosed in my copending application, Serial No. 439,308,

above referred to. Suilce it to say that ywith a length of the priming throat of from 30% to 60% of that of the main throat, and both throats narrower in'width than the blade channel, the efiiciency of the pump forboth priming and liquid pumping* is greatly improved. 'I'he openings 23.and 29 which are termed ports are the most constricted part 'of the pasageways 23a and 29a. k'I'he blades 21 substantially sweep the channel or'pumping space in which they operate. That is` to say, the impeller chamber is concentric with the impeller,.and the impeller has the usual tip lclearance for this type of pump.

The impeller-blades 21 are shown as straight blades which may be eight in number, or of any other desired number, but it is to be understood that the blades Vmay be curved, or may be otherwise arranged than as straight radial blades.

.The blades 21 are open at the upper side, and

terminate at their inner ends about even with the opening through the bottom of the intake chamber I1, providing arecess for the lmore ready ow of liquid being pumped into the blades. The blades 21 are formed integral with the adjacent part of the sleeve, and it has a pair of arms 91, 91 adapted to embrace the inner part of the suction connection I8. Thereby the mainA body of the washer 95, operating through the key 96I and keyway on the sleeve '39, cannot turn in respect of said sleeve 39. Because of the vprojections 91, 91, this assembly is then prev of the current of liquid, which may be corrosive or destructive of the packing.

At itsi lower end the sleeve 39 carries the integral disk l0, which cooperates with the chan- ,nel formed in the sealing member or box in the manner disclosed in my copending application, Serial No. 439,308 aforesaid. The top wall 93 of this sealing chamber or box carries on its undeside, that is, inside the box, the blades d2, which extend to the outer periphery of the disk 90. The lower wall 36 of the sealing box or channel chamber has blades 43 extending out to a point short of the periphery of the sealing disk I0, there being a gap 99 between the ange 35 and the outer margin of the sealing disk 40. of such character that no substantial pressure is developed by the rotation of the parts relative toeach other. The clearance 99 may be 116 of an inch, or more, between the fiange Sii and the margin of the-disk 40, but the blades d2 and I3 have substantial depth of about inch or more so that pressure is developed ln them in accordance with the speed of rotation, the diameter of the blades and the density of the medium acted upon. The longer blades l2 are disposed on the suction side of the plate or disk 40, so that pressure is developed at the full tip of the disk l0 Ilay-movement of the impeller shaft and the sealing box. No substantial pressure is developed in the gap 99 between the margin of the diskl 40 and the flange 35, but liquid will beretained therein for sealing purposes. In the event of-entry of liquid into the blades 13, they will develop pressure in accordance with their a disk 33, which disk closes the space between v diameter, butin nolcase can they develop the same pressure which is developed in the blades I2. Thus the desirable action of maintaining a fulldevelopment of pressure in the blades 42' as against atmospheric pressure will tend to maintain a liquid seal in the gap 99 between the flange 39 and themargin of the disk 49. If, however, the pressure difference is less than that for which the blades 42 are designed to meet, liquid will flow into the lower blades 43 and destruction is that the liquid seal is'capable of developing as against the pressure difference upon the impeller and seal box housing,

which forms is provided with a drain opening 90 which' mayl be disposed at the center of the same, and may be either normallyopen or normally yclosed as desired, or it may be disposed off at one side, and if it is open, it may be employed as an auxiliary priming port, as hereinafter described. The top velop a counter-pressure. The result of this conthe seal, due to suction in the pump, full pressure developed by the blades 42, and yet if this suction is released, liquid will not be, discharged up through the clearance between the shaft 39,`andthe sleeve 39 by the action of the blades 42, since that is balanced by pressure developed by liquid in the blades 43. The result is that the liquid seal is maintained throughout conditions of opzeration from full atmospheric on both sides of theseal to atmospheric on the lower side and full suction on the upper side of the seal.

It will be observed "that the top wall 33 is annular and provides a substantial clearance between the sleeve 39 which is somewhat thickened at the lower end in the form illustrated.` It is also to be observed that the lower end of the shaft 39 has an enlargement. providing a shoulder 44 normallyhaving ample clearance but engageable with a shoulder formed on the sleeve 39, this being for the purpose that vwhen the sleeve 39 is thrust downwardly for disassembly purposes, the shoulder `44 on the shaft will engage the cooperating shoulder on the sleeve to thrust the shaft 39 downwardly, without putting stressupon the rather fragile disk 49. These inliquid which terengaging shoulders might be anywhere along -vsieeve 39 and the shoulder on the upper end of the shaft 39 are adapted to be located against the bottom of the boss 5I and the cap 12 fon the lower end of driving shaft 99, respectively. When these parts are so engaged the disk 49.0n the wall oi` each duct 29a which is formed integral with this member 24 is provided with an vair venting opening 52 which extends out to the Aseparator chamber 20. This opening 52 serves to function in the operation of the pump of redu'cing the time required for the pump to start its orderly operation of taking in priming liquid and evacuating air, as will be described more in detail later. e

As shown in Figure 3, an auxiliary priming'port v` I 53 for entry of liquid may be located atthe bottom of thesidewall of the impeller chamber member 24'. Alternatively, it may be located in the bottom wall near the side wall, i. e., under flange 31. The function and mode of operation of this auxiliary priming port 53, and the function and mode of operation of the air escape port 52, will be vexplained in 'connection with the operation of the pump as a whole. The bearing barrel 9 comprises a tubular member provided with a flange 55 at its lower end,

resting in a recess in the annular bridge plate or ring 1 which in turn rests upon the top of the upper end of the side walls 5. A suitable drain opening, not shown, through the side wall 5 above the closure wall 4 provides for the drain of any y enters the space within these walls. Also a hand-hole, not shown, which may be covered by a plate, is provided through the side wall 5 for manipulation of nut 94. The motor support member 9 comprises an upper annular ring 91,

lower end of the sleeve 39 will be properly located in the sealing box 34.

y The impeller and seal box have a clearance with the side walls and the bottom walls of the chamber member 24. This clearance maybe of the order of 1 to 1A" more or less.v Preferably, the inside sidewalls of the member 24 are slightly enlarged below the portion 24a. of the casing walls which cooperate with the blades 21-as indicated at 24h on Figure 6. The impeller and the appropriate part of the impeller chamber 24 may be of greater diameter than the seal box by stepping the diameters accordingly. With a disk 49 of substantially 4%", and with the construction of the blades 42--43 and non-pressure developing clearance 99 in the seal box shown herein, full difference between maximum suction and atmospheric pressure may be'maintained by a shaft speed from 2900 R. P. M. .up to any end of the shaft section 60. This protecting ring ring 19 has an outlet 11 -through which and a lower annular ring 59 connected by suitable columns 99, whichmay be joined by webs, o r may be separate as desired. Preferably the front part of the motor support 9 is open to permit access tov the coupling not shown, which the motor shaft makes to the shaft section 99 carried in the barrel 9. The motor support 9 and the bearing barrel 9 are clamped to the ring 1, and to each other by the bolts 92. The bearing barrel 9 has a cap or cover 93, with an oil duct 94 through which oil may be conducted to the upper ball 4bearings 95, and then the oil. may run by gravity to the lower radial and thrust ball bearings 99. The inner races ofthe two sets of ball 'bearings 99 and 99 are clamped by shoulders and threaded nuts 91A and 99 to the shaft section 99. The outer race of the bearings 99 rides loosely in the upper end of the barrel 9. and the outer race of the bearing 99 is ilxedly supported by the bearing clamping ring 99 which clamps the outer race between a shoulder on the lower end of the bearing clamp` ring 99l and the lower end of the barrel 9. The shaft section and the bearingsl are adapted lto be withdrawn downwardly from the bearing barrel 9 by release of the bearing clamping ring 99, which is held by bolts 10.- Thereupon the shaft section 99, with its bearings 95 and 99, may be withdrawn downwardly inrespect ofthe barrel 9v or vice versa. A protecting ring 12 is secured by a press or shrink t upon and over the has a radially extending body with a cylindrical ilange 13 `for sealing purposes. An annular oil 15 is supported by an integrai ing 'ring 99 being held by bolts 19. This channel excess oil the bearings.

6 l and other liquid may be drained. The vertical cylindrical flange 13 has rather close clearance, but is out oi' contact with the bearingclamp ring 8B and the ring 16 of the channel member 15, so

that a nlm of oil normally seals the adjacent surfaces of the members 89, 13 and 18 when running, and a pool of oil is trapped inside of 13 when standing. When the shaft stops spinning, the oil runs down through the bearingv SBk and collects in a pool which floods the lower end of bearing B6 beforeit spills over the edge of the-flange. Thus the shaft when it starts up has its heavy duty bearing B6 Hooded with oil. The upper bearing on starting up receives oil from acup through duct 64. Thus both bearings are promptly lubricated on starting up thepump.

Even withA this liquidseal, I discovered that there is danger of breathing of the space within the hollow barrel` 8 when the barrel becomes warmed up by the friction of the rotating shaft and subsequently cools. It isv undesirable to provide openings in the barrel 8 to permit entry and exit of air to satisfy this expansion and contraction of the air inside of the same, because it tends-to draw in impurities which contaminate I solved the problem by providing a llei block 1B which reduces the clearance between it and the shaft section E to so small a volume that breathing is inconsequential. Thus no appreciable vapors or air are drawn in and no dirt or foreign substances can enter the may move between the integral stop tu at the rear and the reiner/'ablel stop d2 at the iront. This stop B2 is preferably mounted on a stud which entends up through the wall of the enlargement 18,

and'i's held by a nut d3. A shoulder 84 may be disposed on the bottom wall to cooperate with the stop B2 and prevent sticking of the body 19 between the stop 82 and the door of the chamber. The body 19 is not large enough to completely ll the opening in the connection when it is against the\back stop 80, but in that position it acts to retard backward now of liquid from the discharge pipe (not shownl which is connected to the 'connection lb. When the ball 19 is in its forward position against the stop $2, there is ample room for full discharge of liquid around the ball 19, and out the connection i9.

in the lower end of the driving shaft Si), and

` pulled tightly into place by the axial tie bolt ab,

to -make a duid-tight joint at this point.` A key 9| ,isY set in a keywayabove the ring 12, and it enters a keyway formed in the upper end of the shaft 38 to key the driving shaft section and the impeller shaft 38 together.

When it is desired to renew the impeller, shaft, andy seal unit, the pump is iirst I opened by removing the top part or section lil from the bottom section I2, cr vice versa, and likewise removing the impeller chamber member 2t. The tie bolt' 93 is unscrewe'd, the motor being ilrst removed, and the` nut 94 is then threaded upwardly, that isbacked off, until it engages the bottom of the ring member l2. It then acts as a screw jack to force the sleeve member 3@ to cngage the shoulder M on the lower end of the impeller shaft, and to pull the impeller shaft outwardly out of the` socket in the shaft section 5Fl, and to push sleeve 39 down in. opening ii oi boss 5l.A The shaft 3B, sleeve- 39, impeller 2l and sealing box are then removed as a unit, and may be replaced by a new unit with fresh packing at 98, and the pump reassembled and put, into op- The pump body'is supported upon a stand 85,

A bar24 may be connected with transverse grooves such as illustrated `in Figure 9, so that the impeller chamber may likewise drain out through the opening of the drain plug 9U. The impeller chamber member 2B is preferably keyed to the bottom section l2 to prevent any rotation of the said member 24 when it is in place, as by means of a projectionl 92 formed on the member 2A, this projection 92 engaging with a boss, not shown, formed in the bottom wall 3 at a suitable place. The impeller shaft 38 is telescopically socketed In the operation of the pump, assuming that the pump is provided with a charge of pruning liquid, this liquid enters the impeller chamber, ilows into the impeller blades, and down through the opening between the sleeve l and the top of the sealing box, and lls the sealing box. The clearance between the shaft 38 and sleeve 3d may be anysuitable ample running clearance Awhich keeps these parts out of contact. In other words, the shaft, the sealing bos and the impeller run freely without contact or close clearance with any stationary part. Since entry o liquid at the top can force .air out through the clearance between the sleeve 3u and the shaft the liquid seal is immediatelyvnlled and established for operation. Assuming that the suction connection i8 is connected to a suitable pipe andthe suction pipe is` sealed with liquid which it is desired to pump, the shaft @il will be driven by the motor which is suitably connected to it. Thereupon liquid standing in the impeller and in the intake `chamber il will immediately be thrown out through the ports 2c and Zic and discharged into the separator. Gas follows, this ges usually being air, and since air is of so light density, being only about soo of the density of liquid, the impeller is not able to blow air of so slight density out against the head of liquid in the separator. However, with a slightl amount of liquid vwhich tends to come in through the ports, a medium somewhat denser than air, but far from as dense as liquid tends to be initially formed, and even this medium may notbe of sumcient density to start delivery through the ports it?! and discharge ducts 28a, since there is a slight head of liquid of the priming charge above these parts. Particularly the driving of gas, that is air, out into the priming throats 29, tends to trap air, in view of the fact that the outer ends of the ducts 29a dip down below the iiange segments dii. Liquid will slowly be worked in through the` rapidly rotating blades and will eventually overcome the so-called priming stall, which is due to the failure of sufficient liquid to reenter to establish an orderly circulation. In the present pump structure, I have provided two independent means for accomplishing the overcoming of this prim the chamber member 2l, the

' at the periphery or it may be formed through the bottom wall of then on the third stage riod of the priming stall" ing stall," one being the provision of an auxiliary priming port which may be through the port 50 or I3, which will allow liquid to seep up through the clearance' and into the 'space blades 21, thereby forming a denser mixture which will begin to form a ilow tending to discharge out through the throats 28 in sulllcient force and volume to establish a discharge. Thereby, by supplying additional liquid in through the clearance-between the rotating sealing box and priming stall may be overcome. Upon the pump becoming primed and filling its intake with liquid, delivery'pressure is established.

The pressure developed by the blades 21 and prevailing at their tips tends to pass through the clearance and down along the sealing box, and out the opening 50. However, this is counteracted by the bottom rotating wall of the sealing box to an extent which tends lto retard or may completely check the inward flow of liquid at the port 50. In fact, the bottom surface of the sealing box, that is, the disk 38, may be bladed', as at lill, in order to set up a counter-pressure to that of the blades 21. Inward ilow from the separator through opening 50 or 53 is counteracted by internal pressure.

Instead of having the auxiliary priming port at the center oi the chamber 24, it may be located as indicated at 53 in Figure 3,

the chamber member 24, at a less radius than the inner cylindrical wallsof the said chamber member 24. y f

It is not necessary that the pressure be completely reversed, that is, raised to a degree to cause liquid to be discharged out of the opening 50 or 53. It is sufficient merely if the iiow be reduced to a value which is inconsequential upon the emciency of the pump. However, this method of supplying additional liquid which will make up a dense enough medium to start the orderly discharge of mixture and reentry of liquid at the priming ports will reduce the time of the scalled priming stall, and accelerate the establishment of orderly evacuation of air from the suction pipe. As soon as this orderly circulation is established, the impeller bladesldischarge a mixture of air and liquid out through the main throats 2 8 and receive reentry of priming liquid at the priming throats 29.

As heretofore stated, the priming operation is usually divided into three stages. namely, the ilrst stage which involves establishing an orderly circulation and filling of the discharge throat with a stream. of mixture which terminates the first stage or priming sta stage.

VThe end of the second stage may be recognized by excessive inow of liquid due to suction on the intake side, resulting in mospheric pressure of'liquid through the return throats 23 in more than adequate volume. From tends to remove air until a point is reached where no further air can be evacuated by the pump at the speed ani under 'the conditions under which it operates.

An alternative -method of shortening the 'peis to provide a ready escape forair out of the main throat,` as by means of the openingsl 52 in the top wall of the ducts 28a' at the throats 28. A .V4 inch opening 52 in one or both of the two ducts 28a tends to allow the air to gravitate outwithout requiring the establishment of a regular disthe forcing by atbetween the v Y charge stream of mixture greatly shortens the initial "priming stall period. In experiments which I have conducted, the priming stall" was cut from 120 seconds to 60 seconds by the expedient of air discharge openings 52 in the main ducts 23a. No substantial interference with the eiiiciency of the pump was caused the presence of the air evacuating openings 52, and such openings 52 may be employed without the introduction of liquid through the auxiliary priming ports 50 or 53 above referred to.

Upon shutting down the motor, the impeller and its sealing box tend to-slow down to a. point where the pump will no longer deliver liquid through the discharge.' or in other words, will no longer maintain the delivery pressure and the air seal. As soon as the delivery pressure drops below the head against which the pump is operating, the liquid will tend to flow back in the discharge and to flow back down the 'suction pipe, and, as per my experience without the flow retarding means shown in Figure l, if the discharge and suction connections are wide open, the dropping of the column in the suction pipe is very rapid, and will rapidly pull liquid down through the discharge pipe, followed by a rush sirable at all events.

of air, which practically cleans the liquid out v of the pump, tending to rob it of l its priming charge.

I have heretofore employed a ilow retarder in the suction connection, as shown in my copend- .ing application above referred to. But I have discovered that there are certain conditions under which the flow retarder in the suction connection produces unsatisfactory results in that checking of the downow'of the suction column does not prevent full pressure of the discharge column from being exerted upon the sealing box and sleeves, with the result that liquid may be squirted out of the sealing sleeve 39. Where the liquid being pumped is either corrosive, or inflammable, this is objectionable. It is unde- I conceived the employ; ment ot the flow retarder I9 in the discharge connecticn, and with the structure shown in Figure 1, when the impeller slows down to the point where the discharge pressure cannot be maintained, liquid drops in the suction connection and pulls air down through the sleeve 39, through through the suction connection to follow the retreating column of liquid. Since the return of liquid from the discharge pipe is retarded to a relatively slow return, the suction connection may be completely emptied of liquid and liquid from the discharge pipe then slowly returns to the separator 26, from whence it flows through the impeller chamber and into the intake connection l1. Any excess drains out through the suction connection I8. It is to be observed that the bottom wall of the suction connection I3 is substantially below the top of the sleeve 39, so that the return of liquid may fill the pump and drain back into the suction connection without flooding the seal, i. e. running out of the top of the sleeve 39. A drain may be provided for the space above the closure i wall 4 for the draining of any liquid back to the source if so desired.

Even if no substantial body of liquid isV retained in the discharge pipe as would be the case when the pipe leads downwardly from the neck i9 the ilow retarder 'I9 appreciably restricts flow of air down through the separator and hence tends to cause air to ilow through filled with air, while the the seal to break the vacuum in the intake.

While the pump above described in connection with Figures l to 8, inclusive, is made ol a suitable metal, designed to resist the attack of the particular liquid being pumped, the invention may be embodied in a porcelain pump, that is,"a pump where the main body portion and so much oi the impeller chamber and other parts as'possible are made of porcelain, or other non-metallic moldable material suitably resistant to the liquids which it may be required to Dump.

In FigureQ I have illustrated a porcelain pump of a structure such that the main working parts parts il and I2 together. The shorter bolts Illb contain, intermediate their ends, transverse pins W6 lying `within an annular groove formed in a metallic ring Idd, which ring is set in' anannular recess in the lower margin of the top section i9 of the pump body. This 'metallic ring IW serves as a clamping or binding means for the lower edge of the side walls of the upper section it, and prevents the application of any sharply concentrated stress which the pins MiB would otherwise apply when the upper part oiy the bolt is put .under tension by screwing dow" the nut Sil. i

ihres or more bolts, such as M5, spaced around the circumference of the body, permit through the pin IM, ring lil and nut lill in each case, of

clamping the bearing support ring 1 to the top oi the cylindrical walls oi the upper section I0. On the same bolts Iii, nuts iut at the lower end clamp the bottom section i2 against the top section id. The longer bolts it! extend through raised bosses lill, so as to distinguish them from the shorter bolts iM and they carry nuts M2 at their upper ends. The bolts iIl4 serve to clamp the pump as a whole including its bearing barrel and motor support upon the supporting base or bracket SS. The bolt M4 in each case carries a nut H31 at its lower end below the ilange 81 of the bracket or base S5, and it extends through a collar IIB and a soft lead washer IIS, and then entends on up through the matching bolt holes IM in the bottom section and the top section, and through the ange l and its distinguishing boss' IIB. At the upper end the nut i I2 puts ten- Sion upon the boltIN to hold the pump upon the base. The pump may be removed from the base 85 by releasing the nuts .I I2 which are distinguishable by the bosses llll.

The pump as a unit may then be lifted completely from the base. Thereupon, to remove the lower section l2, the nuts W9 of the shorter bolts IBS are unscrewed, and the cup-shaped bottom section I may be slid downwardly on the guiding lower ends of the bolts N5. The porcelain impeller and sealing box member 2l may be dropped down with the bottom section i2. If it is desired to remove the ring l. with its motor support and bearing barrel as a unit, this may be done by re` leasing the nuts il on the top end oi the shorter bolts me. b

seal box, is the same as shown in Figure l.

`may be interchangeably `employed in the construction of the pump shown in 'Figure 9. Likewise, the separable arrangement of these working parts as shown in Figure 9 may interchangeably be used in the body of the pump shown in Figure 1.

The assembly of the driving shaft section t@ and the impeller shaft 36, sleeve 39, impeller and In fact, these working parts are identical for both the metal pump .of Figure l and the porcelain or non-metallic pump of Figure 9. `Except for the difference in assembly and disassembly of the body parts of the two pumps, the servicing of the two pumps is the same. Y

Referring to Figures 4, 5 and 8, the priming passageway which opens below the plate 3@ is extended substantially to the outer edge of the plate Sil to insure that the outer end of the passage way isA sealed with liquid during priming. Figure 7 indicates the sections on stations i to li along the axis oi the main discharge passageway 2do and its throat 28, as indicated onFigure i. Similarly Figure 8 shows similar sections taken on similar stations of the priming passageway 2da and its throat 29.

The flow retarder in the discharge connection previously described in connection with Figure l is also employed in the embodiment of Figure 9.

A suitable drain plug 90 is provided in a'metallic insert H25 disposed in the bottom wall of the pump, as shown in Figure 9.

The draining opening 50 shown in Figure 9 is connected to lateral Ibranches formed by a transverse' groove, through which communication between the discharge chamber or separator 2li, and the interior of the impeller and sealing box chamber 24 is provided.

I It is to be understood that like reference numerals in Figures 1 to 8 and in Figure 9 indicate like parts, and that the operation of the pump described in connection with the embodiment oi Figures 1 to 8 applies also to the embodiment of Figure 9.

The pump herein disclosed provides a structure which solves the problems above mentioned, the

essential novelty of which is intended to be covered in the appended claims.

I do not intend to be'limited to the precise details shown and described, except as they are made essential by the appended claims.

I claim: i

1. In a vertical self-priming pump, a cylindrical hollow body comprising substantially cylindrical side walls, an .upper closure wall below the top of said side walls, a bottom wall, walls depending from said upper wall dening an intake chamber, a cup-shaped impeller chamber member resting on said bottom wall and being telescopically joined to said walls of the intake member, an impeller in said impeller chamber, a shaft therefor extending through said upper closure wall, means for maintaining a seal about said shaft, a mounting ring resting upon the upper end oi said sidewalls, a driving shaft barrel resting on said mounting ring, a driving shaft section having antifriction bearings in said barrel and being joined to said impeller shaft, a suction connection en- `tending through the upper part of said sidewalls space between said depending walls and said cylindrical sidewalls. 2..'I'h`e pump of claim 1 wherein the liquid seal box, said box being disposed in the bottom of said impeller chamber member and below the impeller.

3. In a pump of the class described, a. cylindrical hollow body comprising substantially cylindrical side walls, a top closure wall and a bottom wall, the sidewalls extending above the closure wall, a bearing barrel supported on said extended sidewalls and spaced from the top closure wall, internal walls defining an intake chamber within the upper end of the hollow body there being a separator chamber outside said internal walls and inside the hollowy body, an impeller chamber member cooperating with the lower end f of said internal walls to form an impeller and section in said bearing barrel joined-to said irnlpeller shaft section. 4. The pump of claim 3 wherein said shaft section provides a shoulder above the sleeve, the

upper end of the sleeve having a nut threaded thereupon and engageable against the shoulder to force the sleeve downwardly when' thev nut is backed off the sleeve.v f

5. In a pump of the class described, a hollow pump body having a top wall and sidewalls extending ab'ove the same to provide a bearing support for a shaft, a shaft supporting barrel resting on said walls, a sealing sleeve extending through and shouldered against the bottom of said top wall,a driving shaft section supported radially and axially in said barrel, an impeller shaft section extending up through said sleeve and being coupled to the `lower end of said driving shaft section, a nut threaded upon the upper end of the sleeve to clamp the sleeve with its shoulder against the bottom of the top wall, said nut being engageable against a shoulder on the driving shaft section to force the sleeve downwardly when the nut is backed oi.

6. The combination of claim 5 wherein a shoulder on the sealing sleeve is engageable with a shoulder on the lower end of the impeller shaft section to transmit thrust on the sleeve to the impeller shaft section whereby the impeller shaft section and sleeve may be forced down together by backing off said nut.

7. In a pump having a hollow body moulding sidewalls andanupper closure wall, a sealing sleeve extending through said closure wall and shouldered against the bottom thereof, any impeller shaft extending up through said sleeve, a bearing barrel secured to the top of the pump and spaced from the top closure wall, a driving shaft section mounted in antifriction bearings Ain said barrel and having its lower end socketed to receive the ,top of the impeller shaft, a clamping and releasing nut threaded upon the upper end of the sleeve, said nut on backing off being engageable with said driving shaft section to force the sleeve down. u

8. In a vertical self-priming centrifugal pump having a hollow body with a top closure wall, a

' liquid shaftsealing sleeve extending up through the said wall, an impeller shaft extending down through said sleeve and carrying an impeller, there being an intake chamber and a separator shaft is sealed to-the upper closure wall by va sleeve and chamber between said chambers, a. kinetic sealing channel and a disc between said sleeve and shaft 'having an annular gap between them opening into said impeller chamber, a suction connection for said intake chamber adapted to be connected to a suction pipe, a discharge connection for said separator chamber adapted to be connected to a delivery pipe, and a. flow retarder in said discharge connection for retarding but not stopping thereturn now of liquid from the discharge pipe, said gap permitting air to be drawn therethrough into the suction pipe to allow liquid therein t0 ydrop freely while said now retarder restricts the now of uid from` the discharge pipe into the 10. A pump of the class described comprising a closed hollow body of vitreous material, said bodyA having substantially cylindrical sidewalls divided horizontally, vertical bolt holes through the sidewalls for clamping bolts, the lower section comprising a bottom wall, the upper section comprising a top closure wall below the top of the sidewalls, internal depending walls joined to the top closure wall for defining an intake chamber internally thereof, a vitreous impeller housing and duct member resting upon. the-bottom wall and telescoping with the lower end of said depending walls to denne an impeller and sealing box chamber, an impeller and sealing box in said latter chamber, a sealing sleeve extending from said sealing box up through the topwall and clamped thereto, an impeller shaft carrying at its lower end the sealing box and impeller extending up through said sleeve, horizontally extending suction and discharge connections extending from 'said sidewalls above said closure Wall, a

metallic bearing barrel having a mounting flange resting upon said sidewalls, a driving shaft sec- 4 tion having bearings in said barrel and coupled l 1l. In a vertical pump having a hollow to said impeller shaft, and clamping bolts extending vertically through said flange and the` longitudinal bolt holes for clamping said parts together.

body

tion having spaced antifriction bearings carried v on the shaft and mounted in said barrel, said shaft section being joined to said impeller shaft, and a cylindrical filler block in said Vbarrel between said spaced bearings closely embracing said vshaft for reducing the spaceinside said barrel to prevent changes in temperature of said barrel bearing from breathing vapors of corrosive liquids handled by said pump into the bearings.

l2. For use in `a pump of the class described as an article of manufacture, a unitary impeller chamber and duct member comprising a cupchamber in said hollow body and an impeller shaped body having pairs of ports through the sidewalls thereof for the passage of liquid, segmental flanges, one for each pair of ports, and duct containing nozzles for said ports, one nozzle of each pair opening above the corresponding flange segment and the other nozzle of each pair opening below the corresponding ange segment.

13. The article of claim 12 having a central boss on the bottom for supporting the same, and a keying shoulder disposed laterally of the boss for preventing angular movement of the member in use.

14. In a vertical pump of the class described, a horizontally disposed impeller casing, an impeller rotatable therein in a horizontal plane, said casing having internally thereof a peripheral channel which is substantially swept by the impeller, said-casing having a main discharge duct opening through a port into said channel, a priming duct opening through a port adjacent said first port into said channel, the pump having a casing with walls deiining a separator chamber in which' said impeller casingl is disposed, said ducts extending in a generally horizontal direction and opening at their outer ends into said separator chamber, there being an opening for escape of air during the initial stages of priming extending through the top wall of said first duct adjacent the junction of Said duct and said channel.

15. In a vertical pump of the class described, a horizontally disposed impeller casing, an impeller rotatable the'rein in a horizontal plane, said casing having internally thereof a peripheral channel which is substantially swept by the impeller,

' Sad Casing having a main discharge duct opening through a port into said channel, a priming duct opening through a port adjacent said first port into said channel, the pump having a casing with walls deiining a separator chamber in l which said impeller casing is disposed, said ducts extending in a generally horizontal direction and opening at their outer'ends into said separator chamber, there being an auxiliary priming 'opening in the lower part of the impeller casing for reentry of priming liquid into the impeller during theinitial stage of priming, f

16. In a pump of the class described, a cylin-v drical body of vitreous material formed in two sections with meeting annular faces, shaft bear- ,ing support means on the upper section, the lower edge of the top section having an annular recess, a ring disposedin said recess, there being" vertical bolt holes through the bearing,l support and the cylindrical walls of the two sections and the interposed ring, bolts. lying in said holes, said bolts having shoulders for engaging the ring and nuts at the upper ends for holding the bearing support upon the ,upper section, and nuts on the lower ends of the bolts for removably supporting the lower body section.'

17. In combination with the pumpl of claim 16 of a base for supporting the pump and bolts independent of the nrst named bolts extending through the bearing support means, the eylmdrical walls of the pump body and attached to said base.

18. In a pump of the class described, a body comprising two main sections of substantially cylindrical form, namely, a cup-shaped bottom section and an inverted cup-shaped top section, said sections defining a separator chamber, the top section having a centrally perforated top wall and a depending annular wall joined to the top wall near the junction of the tdp wall and s1de vshaft with it. v

`wall to define an intake chamber, said top section `having a substantially cylindrical flange wall extending above its top wall, an annular plate disposed on said flange wall, a bearing-barrel for a drive shaft supported o n said annular plate, a cup-shaped impeller and seal chamber member telescopically joining the depending annular Wall and resting onthe bottom of the bottom section, said impeller and seal chamber member having openings defining ports and passageways for discharge and reentry of liquid between the inside and outside of said latter member, a sealing sleeve secured at its upper end in said central perforation-of the top wail of thetop section and bearing a sealing disc at its lower end, a rotor comprisinga channel member open at the top and closed at the bottom and bearing impeller blades cooperating withv said ports and passageways, a shaft secured to said channel and impeller member and extending through said sleeve and having bearings in said bearing barrel, and discharge and intake connections extending through said ange wall of the top section and communicating with said separator and with intake chamber respectively.

19. A renewable unit comprising a sleeve having its upper end threaded, and having a disl; on its lower end, an impeller 'shaft carrying a circular sealing box providing an internal annular channel cooperating with said disk to provide a kinetic liquid seal, the bottom and sidewalls of the box being closed, the top wall having an opening closely surrounding the sleeve, impeller blades mounted on the top wall of the box in a plane at right angles to the shaft,

said sleeve having an upwardly facing annular locating shoulder, and said shaft having a locating shoulder, said shoulders being adapted to bear against cooperating shoulders on a stationary part and a rotating part, said latter shoulders being so spaced as to ensure a predetermined location of the disk in-said sealing box.

20. The unit of claim 19 wherein the sleeve and the shaft have facing annular shoulders adapted to be engaged endwise when the sleeve is moved downwardly along the shaft whereby the movement of the sleeve downwardly will carry the 21."In"'aI vertical self-priming pump, a hollow pump body comprisingv` an upper transverse wall having a central opening, walls defining an intake trap below said top wall, said trap being open at its bottom, a sealing sleeve having its upper end removably secured and seated in` said central opening, a sealing disc mounted on the lower end of said sleeve, an impeller shaft extending down through the sleeve 'and bearing a channel ring lmember having aninternal channel embracing the margin of the disc, impeller blades carried on said channel ring member, an impeller chamber member having a cylindrical recess and peripheral throats cooperating with said blades, said latter member cooperating with the lower margins of said intake trap walls about said bottom opening to denne an impeller and seal c ber, and said pump body comprising walls d'ening a separator chamber outside of and surrounding said impeller chamber and communicating with said throats.

22. The pump of claim 21 wherein the impeller chamber member is a substantially cup shaped member piloted upon said margins of the intake trap wall, and the lower part of the bodyv Wall forming the separator chamber is a cup shaped member upon the inside of which is seated said impeller chamber member.

23. The combination of claim 21 whereinthel pump body has side walls extending above the upper transverse Wall, a bearing barrel having anti-friction bearings and a drive shaft section therein supported upon said walls, said drive shaft section and the upper end of the impeller shaft having a telescopic driving connection,

24. A unitary impeller and seal structure comprising a sleeve shouldered externally at a point adjacent its upper end and threaded at its upper end to receive a clamping nut, an annular disc integral with the lower` end of the sleeve, an im-l lthrust exerted downwardly upon the sleeve dlrectly to the lower end of the impeller shaft.

25. In a centrifugal pump, an impeller and seal structure comprising a sleeve shouldered externally at a point adjacent its upper end and threaded at its upper end to receive a clamping nut,4 a clamping nut engageable on said threaded upper end, an annular disk integral with the lower end of the sleeve, an impeller shaft extending through the sleeve and bearing a boxlike channel member embracing the margin of the disk, said channel memberbeing open at the top where it. embraces the sleeve and bearing at its tcp impeller blades to constitute a pumping impeller, the sleeve and impeller shaft having interengaging shoulders for transmitting thrust exerted downwardly upon the sleeve directly to the lower end of the impeller section telescopically joined to said impeller shaft, said shaft section presenting a shoulder engageable by said nut when the same is backed off to permit the nut to exert a downward thrust upon the sleeve.

HARRY E. LA BOUR.

shaft, and a driving shaft' 

